Support for DID PRISM

[FabioPinheiro]

Background

• Existing DID Peer is static; identities cannot be modified post-creation, as you may have to do eg when changing home address
• DID Prism is modifiable (it lives on the Cardano Blockchain), so needs to be supported
• We will continue to support DID Peer for compatibility (ie this is not a breaking change)

DoD

• All interactions of the Mediator work with a DID Prism as they have previously worked with a DID Peer

How to Test

• Set up Mediator to use PRISM DID only
• E2E Test Suite stays green (tested against short URIs only)
• Integration Test that "returns correct DID document for the both short & long form URIs" is green

Implementation Details/Hints

1. Add support for did:prism by adding a resolver for DID PRISM.
2. Use a did:prism DID as the agent/identity in the mediator.
3. Integration Test in DoD needs to be created

[FabioPinheiro]

My plan is the strip the logic of configuring/generating the did:peer.

Instead, the user would put the DID himself. So we need another tool/cli to help the user create the DID.
The user would also configure the private keys and resolvers.
The Mediator will resolve the DID and check the keys when initializing.

[pparker]

Refinement discussion today of me/Fabio/Allain, ticket is R4D.

[pparker]

Next step:

• @FabioPinheiro has a PR, 0.5 - 1 day away from needing reviews
• his prios have changed, he's not currently working on this one, it'll probably be a month or two before that changes